Hi Metalgreg!
You can use "tetsudau" for "to help" or " to assist" generally.
If you would like to say "Can you help me learn Japanese?", you can also use "tetsudau". For example, 日本語の勉強を手伝ってくれますか。/ 日本語を勉強するのを手伝ってくれますか?
In this sentence, the verb is conjugated into the patter of "verb+ tekureru". It is used when you ask someone for a favour. The pattern literally mean "to give a favour of doing". If the pattern applied to "tetsudau," it becomes "tetsudattekureru."
I hope my answer helped you in some way.